When considering IP cameras or IP camera equipment for outdoor surveillance you may see a number attached to each product such as 'IP66' or 'IP54' etc. Not to be confused with IP address, this number is known as the product's IP rating.
The International Protection Rating (IP rating), sometimes known as 'Ingress Protection Rating', is an international standard used to describe the environmental protection of electrical equipment or enclosures for electrical equipment.
The standard is designed to give more information about the level of protection other than merely stating the equipment is "water-proof" and is normally expressed as a two-digit number where the first number indicates the level of protection against the ingression of solid objects and the second digit indicates the level of protection against the ingression of liquids. Note: If the IP rating shows a 'X' then there is no level of protection for that specific category.
The full tables showing all ratings can be viewed here but when considering the IP rating in relation to a network camera we are only interested in a number greater than 4 or 5 as these would signify that camera would be suitable for outdoor use.
Common IP ratings for IP cameras
IP66
The first digit (6) indicates the camera is dust tight giving complete protection against any solid matter entering the equipment. The second digit (6) indicates the camera is protected against powerful jets of water meaning that a powerful jet can be aimed at the camera from any direction with no harmful effect. This would indicate the camera is completely impervious to damage from natural elements and can be placed in any outdoor location.
IP65
A camera with an IP65 rating has the same level of protection against dust but slightly less protection against liquids but having a rating of 5 for liquids will mean that it can withstand jets of water projected by a nozzle from any direction and would still be suitable for any outdoor location. A lot of rugged IP cameras have this rating and they work without fail in demanding environments.
IP54
This IP rating is given to a camera which requires a little more attention when being placed outdoors. The first digit (5) indicates resistance to dust. It's not completely impervious to dust but any dust which does enter will not have any harmful effect on the equipment. The second digit (4) indicates the camera is resistant to splashing water. Splashes hitting the camera from any angle will have no harmful effect.
A camera with an IP54 rating will be fine outdoors but a little more protection should be given such as placing the camera under the eaves of a home or business. It should be noted that some IP cameras can be mounted outdoors with no extra protection and for other IP cameras protective housings will provide these ratings (and protection) so they can provide outdoor surveillance for any IP CCTV security monitoring system.